Modulator arrays, and modulation devices and medical imaging apparatuses including the same

ABSTRACT

A method includes: controlling a first layer of a panel so that first electrical signals generated based on the first driving signal are applied to first cells of the first layer, and light incident on the first layer is modulated into a first modulated light according to the first electrical signals; and controlling a second layer of the panel so that second electrical signals generated based on the second driving signal are applied to second cells of the second layer, and the first modulated light received from the first layer is modulated into a second modulated light according to the second electrical signals. A modulation resolution of the second modulated light output from the second layer is greater than that of the first modulated light due to at least two second cells of the second layer that modulate light modulated by one first cell of the first layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/313,349, filed Jun. 24, 2014, which claims priority from KoreanPatent Application No. 10-2013-0116895, filed Sep. 30, 2013, in theKorean Intellectual Property Office. The disclosures of the above-listedapplications are incorporated herein by reference in their entireties.

BACKGROUND 1. Field

The present disclosure relates to modulator arrays, and modulationdevices and medical imaging apparatuses including the same.

2. Description of the Related Art

In the medical imaging field, the demand for information about a tissueof a living body and for imaging technologies are increasing.

For example, many cancers occur under an epithelial cell, andmetastasize inside a hypodermal cell. Therefore, when it is possible toearly detect cancer, a damage caused by the cancer is considerablyreduced. A related art imaging technology uses a magnetic resonanceimaging (MRI), a computed tomography (CT), ultrasound, or the like, toimage an internal tomography through the skin. However, since the imageresolution is low, it is impossible to early detect a small-size cancer.

On the other hand, an optical coherence tomography (OCT), an opticalcoherence microscopy (OCM), and a photoacoustic tomography (PAT) may uselight to diagnose early stages of cancer. Although a skin penetrationdepth may be as low as 1 mm to 2 mm, for the OCT, or 50 mm to 50 mm, forthe PAT, a resolution is higher by about ten to twenty times than, forexample, of the ultrasound, and, thus, these technologies may usefullydiagnose incipient cancer.

Thus, in these technologies, there is a need for apparatuses and methodsto achieve the light with a controllable wavefront, to be capable ofcapturing an image deep inside of a bio-tissue, even when the skintissue penetration of the incident light is low.

SUMMARY

Exemplary embodiments address at least the above problems and/ordisadvantages and other disadvantages not described above. Also, theexemplary embodiments are not required to overcome the disadvantagesdescribed above, and may not overcome any of the problems describedabove.

One or more exemplary embodiments provide modulator arrays that controla wavefront of light by using a plurality of optical modulators, andmodulation devices and medical imaging apparatuses including the same.

According to an exemplary embodiment, a modulator array includes: afirst optical modulator that shapes a wavefront of light into aplurality of first shape wavefronts to modulate the light; and a secondoptical modulator that shapes at least one of the plurality of firstwavefronts into a plurality of second shape wavefronts to modulate thelight output from the first optical modulator.

A boundary between adjacent wavefronts of the plurality of second shapewavefronts may be discontinuous.

The first and second optical modulators may partially overlap each otherwith respect to a path of propagation of light.

The first and second optical modulators may be arranged cornerwise withrespect to a vertical direction of the path of propagation of light.

At least one of the first and second optical modulators may include aplurality of cells that modulate at least one of a size and a phase ofincident light.

The plurality of cells may be arranged vertically to the path ofpropagation of light.

Adjacent cells of the plurality of cells modulate incident light intolight having different phases.

At least one cell included in the first optical modulator may overlap aplurality of cells included in the second optical modulator.

At least one of the first and second optical modulators may include atleast one of liquid crystal on silicon (LCoS) and a deformable mirror(DM).

A first driving signal of the first optical modulator and a seconddriving signal of the second optical modulator may be synchronized witheach other.

The first and second driving signals may have the same period anddifferent phases.

A phase difference between the first and second driving signals may beshorter than a period of the first driving signal.

According to an exemplary embodiment, a modulation device includes: themodulator array; and a modulation controller that controls at least oneof a position and a driving signal of at least one optical modulator ofthe modulator array to increase a modulation resolution of light passingthrough the modulator array.

The modulation controller may control a degree of overlapping betweenthe optical modulators of the modulator array with respect to a path ofpropagation of light.

The modulation controller may control at least one of the first andsecond optical modulators so that one cell of the first opticalmodulator overlaps a plurality of cells included in the second opticalmodulator.

The modulation controller may move at least one of the first and secondoptical modulators in a vertical direction of the path of propagation oflight.

The modulation controller may control a phase difference between a firstdriving signal of the first optical modulator and a second drivingsignal of the second optical modulator.

The phase difference may be shorter than a period of the first drivingsignal.

According to an exemplary embodiment, a medical imaging apparatusincludes: a light source; the modulator array that modulates lightoutput from the light source; and a probe that is inserted into a bodycavity, and irradiates light, output from the modulator array, onto aninternal object of the body cavity.

The medical imaging apparatus may further include an interferometer thatsplits the light, output from the modulator array, into measurementlight and reference light, transfers the measurement light to the probe,and receives response light corresponding to the measurement light fromthe probe to cause coherence between the measurement light and thereference light, wherein the medical imaging apparatus may use anoptical coherence tomography (OCT) technology.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will be more apparent by describingcertain exemplary embodiments with reference to the accompanyingdrawings, in which:

FIG. 1 is a diagram illustrating a modulator array according to anexemplary embodiment;

FIGS. 2, 3, and 4 are diagrams exemplarily illustrating an arrangementrelationship between first and second optical modulators;

FIGS. 5 and 6 are exemplary diagrams for describing an overlappingrelationship between a plurality of optical modulators according to anexemplary embodiment;

FIG. 7 is a reference diagram for describing a method of increasing atime resolution according to an exemplary embodiment;

FIG. 8 is a block diagram illustrating a medical imaging apparatusaccording to an exemplary embodiment; and

FIG. 9 is a diagram illustrating an optical coherence tomography (OCT)apparatus corresponding to an exemplary embodiment of the medicalimaging apparatus.

DETAILED DESCRIPTION

Exemplary embodiments are described in greater detail with reference tothe accompanying drawings.

In the following description, like drawing reference numerals are usedfor like elements, even in different drawings. The matters defined inthe description, such as detailed construction and elements, areprovided to assist in a comprehensive understanding of the exemplaryembodiments. However, it is apparent that the exemplary embodiments canbe practiced without those specifically defined matters. Also,well-known functions or constructions are not described in detail sincethey would obscure the description with unnecessary detail.

Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list. In the drawings, the size of eachelement may be exaggerated for clarity and convenience of description.

FIG. 1 is a diagram illustrating a modulator array 100 according to anexemplary embodiment. As illustrated in FIG. 1, the modulator array 100may include a first optical modulator 110, which shapes a wavefront ofincident light into a plurality of first shape wavefronts to modulatethe light, and a second optical modulator 120 that shapes at least oneof the plurality of first wavefronts into a plurality of second shapewavefronts to modulate the light output from the first optical modulator110. The shape wavefront is a partial region of a wavefront. Internaldots of the shape wavefront are continuous, but a boundary between theshape wavefronts is discontinuous. This is because below-described cellsmodulate light to have different phases.

The first and second optical modulators 110 and 120 are disposed on apath of propagation of light. Therefore, the light is primarilymodulated by the first optical modulator 110 as the incident lightpasses, and is secondarily modulated by the second optical modulator 120as the primarily-modulated light passes. Each of the first and secondoptical modulators 110 and 120 may be configured with a plurality ofcells that modulate at least one of a size and a phase of incidentlight. Adjacent cells of the plurality of cells modulate incident lightto have different phases. The plurality of cells may be arranged in adirection across a path of propagation of light, and may be arrangedprimarily or secondarily.

The first optical modulator 110 may spatially shape light. The firstoptical modulator 110 may be at least one of liquid crystal on silicon(LCoS) and a deformable mirror (DM).

The LCoS is manufactured by coating liquid crystal on a surface of asilicon wafer, and thus reflects incident light to modulate the incidentlight. Phase modulation of light may be changed according to a positionof the liquid crystal, and the position of the liquid crystal may bechanged according to a driving signal, for example, an applied voltage.One LCoS may shape a wavefront of the incident light into a plurality ofshape wavefronts. Here, each of some regions of the LCoS, whichmodulates the incident light to have the same phase, may be a cell. Inthe first optical modulator 110, a plurality of the LCoS may bearranged, and one LCoS may modulate the incident light to have the samephase. In this case, each of the plurality of the LCoS may be a cell.

The DM deforms a shape of a reflective surface to modulate light. Phasemodulation of the light may be changed according to a bent shape of thereflective surface, and the shape of the reflective surface may bechanged according to a driving signal, for example, an applied voltage.One DM may shape a wavefront of incident light into a plurality of shapewavefronts. Here, each of some regions of the DM, which modulates theincident light to have the same phase, may be a cell. In the firstoptical modulator 110, a plurality of the DMs may be arranged, and oneDM may modulate the incident light to have the same phase. In this case,each of the plurality of DMs may be a cell.

The second optical modulator 120 is disposed on the path of propagationof light, and light obtained through modulation by the first opticalmodulator 110 is incident onto the second optical modulator 120. Thesecond optical modulator 120 may additionally shape a shape wavefront ofthe incident light with respect to at least one of a space and a time.The second optical modulator 120 may be at least one of the LCoS and theDM.

The first and second optical modulators 110 and 120 may be disposed tooverlap some regions thereof with respect to the path of propagation oflight. Therefore, at least one of a plurality of shape wavefrontsobtained through shaping by the first optical modulator 110 may beshaped into a plurality of shape wavefronts while passing through thesecond optical modulator 120. In FIG. 1, for convenience of description,the modulator array 100 is illustrated as including the first and secondoptical modulators 110 and 120, but the modulator array 100 may includethree or more optical modulators.

FIGS. 2 to 4 are diagrams exemplarily illustrating an arrangementrelationship between first and second optical modulators 110 and 120.For convenience of description, it is assumed that the number of cellsof the first optical modulator 110 is the same as the number of cells ofthe second optical modulator 120. However, the assumption is only forconvenience of description, and the present exemplary embodiment is notlimited thereto. The number of cells of the first optical modulator 110may differ from the number of cells of the second optical modulator 120.

As illustrated in FIG. 2, the first optical modulator 110 may includefour cells a11, a12, a21 and a22. Adjacent cells modulate a wavefront ofincident light into a plurality of shape wavefronts having differentphases. Therefore, a wavefront of light incident onto the first opticalmodulator 110 may be modulated into four different shape wavefronts, andthe modulated light may be output.

The second optical modulator 120 may be disposed in a lower directionwith respect to the first optical modulator 110, i.e., in a directionparallel to the Y-axis (illustrated in FIG. 1) and perpendicular to adirection of the incident light in FIG. 2. First and second cells a11and a12 of the first optical modulator 110 may partially overlap firstand second cells b11 and b12 of the second optical modulator 120, andthird and fourth cells a21 and a22 of the first optical modulator 110may partially overlap first and third cells b11 and b21 and second andfourth cells b12 and b22 of the second optical modulator 120,respectively. A wavefront of light incident onto the modulator array 100is output as the following shape wavefront according to the positionarrangement of the first and second optical modulators 110 and 120.

Specifically, a portion of a shape wavefront of light obtained throughmodulation by the first cell a11 of the first optical modulator 110 ismodulated by the first cell b11 of the second optical modulator 120.Therefore, light incident onto the first cell a11 of the first opticalmodulator 110 of the modulator array 100 may be output as two shapewavefronts having different phases. That is, in the modulator array 100,the light incident onto the first cell a11 of the first opticalmodulator 110 may be modulated into two shape wavefronts havingdifferent phases by the first cell a11 and a first overlapping cell c11,and the modulated shape wavefronts may be output. Here, an overlappingcell is a region in which the cell of the first optical modulator 110overlaps the cell of the second optical modulator 120, and light ismodulated by the first and second optical modulators 110 and 120.

A portion of a shape wavefront of light obtained through modulation bythe second cell a12 of the first optical modulator 110 is modulated bythe second cell b12 of the second optical modulator 120. Therefore, inthe modulator array 100, light incident onto the second cell a12 of thefirst optical modulator 110 may be modulated into two shape wavefrontshaving different phases by the second cell a12 and the first overlappingcell c12, and the modulated shape wavefronts may be output.

Similarly, a shape wavefront of light obtained through modulation by thethird cell a21 of the first optical modulator 110 is modulated by thefirst and third cells b11 and b21 of the second optical modulator 120,and is output as two shape wavefronts having different phases, and thus,light incident onto the third cell a21 of the first optical modulator110 is modulated into two shape wavefronts having different phases bythird and fifth overlapping cells c21 and c31. A shape wavefront oflight obtained through modulation by the fourth cell b22 of the secondoptical modulator 120 is also modulated into two shape wavefronts havingdifferent phases by the second and fourth cells b12 and b22 of thesecond optical modulator 120, and the modulated shape wavefronts areoutput. That is, light incident onto the fourth cell a22 of the firstoptical modulator 110 is the same as a result in which the light ismodulated into two shape wavefronts having different phases by fourthand sixth overlapping cells c22 and c32. In addition, although notpassing through the first optical modulator 110, there may be light thatpasses through the third and fourth cells b21 and b22 of the secondoptical modulator 120. The light passing through the third and fourthcells b21 and b22 of the second optical modulator 120 is phase-modulatedand output. Therefore, light passing through the first and secondoptical modulators 110 and 120 is output as light having six shapewavefronts in an overlapping region between the first and second opticalmodulators 110 and 120. As a result, each of the optical modulatorsincludes four cells, but when the optical modulators are arranged tooverlap each other, light may be modulated by eight cells.

The first and second optical modulators 110 and 120 may be arranged witha displacement in a left or right direction with respect to the path ofpropagation of light, i.e., in a direction parallel to the X-axis(illustrated in FIG. 1) and perpendicular to a direction of the incidentlight in FIG. 2, and may partially overlap each other.

For example, as illustrated in FIG. 3, a wavefront of light incidentonto the first optical modulator 110 is modulated into four differentshape wavefronts, and the modulated shape wavefronts are output. Thesecond optical modulator 120 is disposed conerwise in a right directionwith respect to the first optical modulator 110. The first and thirdcells a11 and a21 of the first optical modulator 110 overlap the firstand third cells b11 and b21 of the second optical modulator 120, and thesecond and fourth cells a12 and a22 of the first optical modulator 110may partially overlap the first and second cells b11 and b12 and thethird and fourth cells b21 and b22 of the second optical modulator 120,respectively. A wavefront of light incident onto the modulator array 100may be modulated as follows according to the position arrangement of thefirst and second optical modulators 110 and 120.

Specifically, a portion of a shape wavefront of light obtained throughmodulation by the first cell a11 of the first optical modulator 110 ismodulated by the first cell b11 of the second optical modulator 120, anda portion of a shape wavefront of light obtained through modulation bythe third cell a21 of the first optical modulator 110 is modulated bythe third cell b21 of the second optical modulator 120. That is, in themodulator array 100, light incident onto the first cell a11 of the firstoptical modulator 110 is modulated into two shape wavefronts havingdifferent phases by the first cell a11 and the first overlapping cellc11, and light incident onto the third cell a21 of the first opticalmodulator 110 is modulated by the third cell a21 and a fourthoverlapping cell d31.

A shape wavefront of light obtained through modulation by the secondcell a12 of the first optical modulator 110 is modulated by the firstcell b11 and second cell b12 of the second optical modulator 120, and isthereby output as two shape wavefronts having different phases. A shapewavefront of light obtained through modulation by the fourth cell b22 ofthe second optical modulator 120 is modulated by the third and fourthcells b21 and b22 of the second optical modulator 120, and is therebyoutput as two shape wavefronts having different phases. That is, in themodulator array 100, light incident onto the second cell a12 of thefirst optical modulator 110 is modulated by second and third overlappingcells d12 and d13, and light incident onto the fourth cell a23 of thefirst optical modulator 110 is modulated by the fourth and fifthoverlapping cells d22 and d23.

Therefore, light passing through the first and second optical modulators110 and 120 is output as light having six shape wavefronts in theoverlapping region between the first and second optical modulators 110and 120.

The first and second optical modulators 110 and 120 may be arrangedcornerwise in a diagonal direction with respect to the path ofpropagation of light, and may partially overlap each other. For example,as illustrated in FIG. 4, the second optical modulator 120 is disposedconerwise in a right upper direction with respect to the first opticalmodulator 110. The modulator array 100 may form a first overlapping celle11 by overlapping between the first cell a11 of the first opticalmodulator 110 and the first cell b11 of the second optical modulator120, and may form a fourth overlapping cell e21 by overlapping betweenthe first cell a11 of the first optical modulator 110 and the third cellb21 of the second optical modulator 120. Also, the modulator array 100may form second, third, fifth, and sixth overlapping cells e12, e13, e22and e23 by overlapping between the second cell a12 of the first opticalmodulator 110 and the first to fourth cells b11, b12, b21 and b22 of thesecond optical modulator 120. The modulator array 100 may form a seventhoverlapping cell e31 by overlapping between the third cell a21 of thefirst optical modulator 110 and the third cell b21 of the second opticalmodulator 120, and may form eighth and ninth overlapping cells e32 ande33 by overlapping between the fourth cell a22 of the first opticalmodulator 110 and the third and fourth cells b21 and b22 of the secondoptical modulator 120.

Therefore, light passing through the modulator array 100 is output aslight having nine shape wavefronts in the overlapping region between thefirst and second optical modulators 110 and 120.

FIGS. 5 and 6 are exemplary diagrams for describing an overlappingrelationship between a plurality of optical modulators according to anexemplary embodiment.

As illustrated in FIG. 5, the cell arrangement a11 and a21 of the firstoptical modulator 110 may differ from the cell arrangement b11 and b12of the second optical modulator 120. Therefore, the modulator array 100forms four overlapping cells f11, f12, f21 and f22 by overlappingbetween the first and second optical modulators 110 and 120. As aresult, the first optical modulator 110 may shape a wavefront of lightinto a plurality of shape wavefronts, and the second optical modulator120 may shape at least one of a plurality of shape wavefronts, obtainedthrough shaping by the first optical modulator 110, into a plurality ofshape wavefronts.

As illustrated in FIG. 6, the number of cells a11 and a21 of the firstoptical modulator 110 may differ from the number of cells b11 and b12 ofthe second optical modulator 120. Therefore, the modulator array 100forms eight overlapping cells g11 to g24 by overlapping between thefirst and second optical modulators 110 and 120. As a result, the firstoptical modulator 110 may shape a wavefront of light into a plurality ofshape wavefronts, and the second optical modulator 120 may shape atleast one of a plurality of shape wavefronts, obtained through shapingby the first optical modulator 110, into a plurality of shapewavefronts.

As described above, in arranging a plurality of optical modulators withrespect to the path of propagation of light, when one cell of the firstoptical modulator 110 is disposed to overlap a plurality of cells of thesecond optical modulator 120, light passing through the modulator array100 may be modulated into light having more shape wavefronts. Therefore,the modulator array 100 increases a space resolution of modulation. Whenthe space resolution of modulation increases, light obtained throughmodulation by different optical modulators increases an energyefficiency in the path of propagation of light, thereby increasing atransmission depth.

Moreover, the modulator array 100 increases a time resolution ofmodulation. FIG. 7 is a reference diagram for describing a method ofincreasing a time resolution according to an exemplary embodiment.

As illustrated in FIG. 7, the driving signal may be synchronized betweenfirst and second optical modulators 110 and 120, disposed with adistance d from one another. The driving signal of the first opticalmodulator 110 and the driving signal of the second optical modulator 120may have the same period, but may have different phases. A phasedifference between the driving signal of the first optical modulator 110and the driving signal of the second optical modulator 120 may be“π/(n*m)” (where n is the number of optical modulators in a modulationdevice, and m is a natural number).

Since the driving signal of the first optical modulator 110 and thedriving signal of the second optical modulator 120 have differentphases, light incident onto the modulator array 100 may be shaped into aplurality of shape wavefronts according to the driving signal of thefirst optical modulator 110, and the plurality of shape wavefronts maybe additionally shaped according to the driving signal of the secondoptical modulator 120. That is, light passing through the modulatorarray 100 may be controlled a plurality of times according to thedriving signal of the first optical modulator 110 and the driving signalof the second optical modulator 120. When a detector having a timeresolution earlier than the driving signal of the first opticalmodulator 110 is used, a modulation result of the second opticalmodulator 120 may be checked within a driving period time of the firstoptical modulator 110. As a result, in terms of the detector, an effectin which modulation shorter than a period of the first optical modulator110 is performed is obtained in overall light modulation.

The above-described modulator array 100 may be applied to medicalimaging apparatuses that acquire information about an object by usingoptical coherence. The space resolution of the modulator array 100 maybe determined by a relative position relationship between the opticalmodulators with respect to the path of propagation of light or a cellarrangement of each modulator itself, and the time resolution of themodulator array 100 may be determined by a distance between the opticalmodulators or the driving signals of the optical modulators. Therefore,the medical imaging apparatuses may modulate light by adjusting a time,a space, a time resolution, or a space resolution depending on the case.

FIG. 8 is a block diagram illustrating a medical imaging apparatusaccording to an exemplary embodiment. Referring to FIG. 8, a medicalimaging apparatus 200 includes an optical output unit 210, a modulatorarray 220, a modulation controller 230, a detector 240, and a signalprocessor 250. The medical imaging apparatus 200 of FIG. 10 isillustrated as including only elements relevant to the present exemplaryembodiment. Therefore, it can be understood by one of ordinary skill inthe art that the medical imaging apparatus 200 may further includegeneral-use elements in addition to the elements of FIG. 8.

The medical imaging apparatus 200 according to the present exemplaryembodiment is an apparatus that acquires a tomography image of an objectby using light, and examples of the medical imaging apparatus 200include a11 of the optical imaging apparatuses that may acquire atomography image based on optical coherence, i.e., OCT apparatuses, OCMapparatuses, optical microscopes, etc.

The optical output unit 210 outputs light incident onto an object 10. Inthis case, the optical output unit 210 may output a wavelength-sweptlight, a laser, or the like, but is not limited to thereto. Light outputfrom the optical output unit 210 passes through the modulator array 220,and is incident onto the object 10.

The modulator array 220 shapes light temporally or spatially. Forexample, the modulator array 220 may modulate a wavefront of light intoa plurality of shape wavefronts, and may change the number ofmodulations. In this case, in the modulator array 220, an LCoS or a DMmay be disposed on a path of propagation of light. The modulator array,which has been described above with reference to FIGS. 1-7 is applicablehere, and, thus, its detailed description is not provided.

The modulation controller 230 may control modulation of light byadjusting at least one of a distance and a relative position betweenoptical modulators of the modulator array 220 and driving signals of theoptical modulators. For example, when intending to increase a spaceresolution, the relative position between the optical modulators may beadjusted. When intending to increase a time resolution, at least one ofthe distance between the optical modulators and the driving signals maybe adjusted.

The detector 240 detects light acquired from light that passes throughthe modulator array 220 and is incident onto the object 10. The lightacquired from the light incident onto the object 10 denotes light thatis incident onto the object 10 and is acquired through transmission,reflection, and scattering. For example, the acquired light may be lightthat is acquired by coherence between reference light and response lightacquired from the light incident onto the object 10. As another example,the acquired light may be light that is acquired by coherence between asecondary harmonic signal of the response light and a secondary harmonicsignal of the reference light. However, the present exemplary embodimentis not limited thereto.

The signal processor 250 signal-processes a signal detected by thedetector 240 to generate a tomography image. For example, the detector240 may detect a spectrum signal corresponding to each shape wavefront,and the signal processor 250 may signal-process the detected spectrumsignal to generate the tomography image.

The medical imaging apparatus 200 may further include an opticalcontroller (not shown). The optical controller may determine a region ofinterest (ROI) corresponding to a transmission depth in which light isfocused on the object 10, and control the light in order for the lightto be focused on the determined ROI. The optical controller maydetermine a plurality of ROIs having different transmission depths inwhich the light is focused on the object 10. Therefore, the opticalcontroller may control the light in order for the light to besequentially focused on the plurality of ROIs.

FIG. 9 is a diagram illustrating an optical coherence tomography (OCT)apparatus 300 as an example of the medical imaging apparatus of FIG. 8.Referring to FIG. 9, the OCT apparatus 300 may include an optical outputunit 310, a modulator array 321, a modulation controller 330, a detector340, a signal processor 350, and may further include an interferometer370 and an optical probe 380. The above-described details of the opticaloutput unit 210, the modulator array 220, the modulation controller 230,the detector 240, and the signal processor 250 of FIG. 8 may be appliedto the optical output unit 310, the modulator array 321, the modulationcontroller 330, the detector 340, and the signal processor 350 of FIG.9, and thus, the same descriptions provided with regard to the elementsare not repeated.

The optical output unit 310 transfers output light to the interferometer370. According to an exemplary embodiment, the modulator array 321 maybe disposed between the optical output unit 310 and the interferometer370. Therefore, light having a phase obtained through modulation by themodulator array 321 may be transferred to the interferometer 370.

The modulator array 321 modulates a phase of light according to arelative position relationship and a distance between optical modulatorsof the modulator array 321 and driving signals of the opticalmodulators. The OCT apparatus 300 may modulate a phase of at least oneof light emitted from the optical output unit 310, measurement light,and reference light. Referring to FIG. 9, the modulator array 321 of theOCT apparatus 300 may be disposed between optical output unit 310 andthe interferometer 370, between a reference mirror 374 and a beamsplitter 372 of the interferometer 370, or at a position of the probe380 on which the measurement light split by the beam splitter 372 isincident.

The modulator array 330 may adjust the relative position relationshipand the distance between the optical modulators of the modulator array321 and a delay of the driving signals according to a predeterminedresolution. The predetermined resolution may be set by a user using theOCT apparatus 300, or may be automatically set according to a kind of anobject.

The interferometer 370 splits light (which is output from the opticaloutput unit 310) into the measurement light and the reference light,irradiates the measurement light onto the object 10, and receivesresponse light generated from the measurement light reflected by theobject 10.

The interferometer 370 may include the beam splitter 372 and thereference mirror 374. Light transferred from the optical output unit 310is split into the measurement light and the reference light by the beamsplitter 372. Among the light obtained through split by the beamsplitter 372, the measurement light is transferred to the optical probe380, and the reference light is transferred to the reference mirror 384and returns to the beam splitter 382. The measurement light transferredto the optical probe 380 is irradiated onto the object 10 of which aninternal tomography image is to be captured by using the optical probe380, and the response light generated from the measurement lightreflected from the object 10 is transferred to the beam splitter 372 ofthe interferometer 370 through the optical probe 380. The transferredresponse light and the reference light reflected by the reference mirror374 causes coherence in the beam splitter 372.

The optical probe 380 may include a collimator lens 382, a galvanoscanner 384, and a lens 386. Here, the galvano scanner 384 is a mirrorthat rotates in a certain radius about a certain axis, and may beimplemented with a micro electro mechanical system (MEMS) mirror thatobtains driving force necessary for rotation from an MEMS. Themeasurement light transferred from the interferometer 370 passes throughthe collimator lens 382 of the optical probe 380 to thereby becollimated. The collimated measurement light is reflected by the galvanoscanner 384, and thus, a propagating direction of the measurement lightis adjusted. The direction-adjusted measurement light passes through thelens 386, and is irradiated onto the object 10.

In the above descriptions of the medical imaging apparatus, an exampleusing the OCT apparatus is provided, but the modulator array may beapplied to various medical imaging apparatuses such as PAT apparatuses,OCM apparatuses, etc. In this case, a receiver may include a detectionsensor suitable for a kind of a signal generated from an object, and anappropriate image signal processing method may be used.

According to the above-described exemplary embodiments, the modulatorarray shapes a wavefront of light by using a position relationshipbetween a plurality of optical modulators and an arrangementrelationship between cells included in each of the optical modulators,thereby increasing the space resolution of modulation. The modulatorarray controls a position or a driving signal of each of the opticalmodulators, thereby increasing the time resolution of modulation. Theabove-described optical probe may be applied to medical imagingapparatuses.

The foregoing exemplary embodiments and advantages are merely exemplaryand are not to be construed as limiting. The present teaching can bereadily applied to other types of apparatuses. Also, the description ofthe exemplary embodiments is intended to be illustrative, and not tolimit the scope of the claims, and many alternatives, modifications, andvariations will be apparent to those skilled in the art.

What is claimed is:
 1. A method of controlling a panel, the panelcomprising a first layer that includes first cells disposed adjacent toone another and a second layer that includes second cells disposedadjacent to one another, the method comprising: controlling the firstlayer using a first driving signal so that first electrical signalsgenerated based on the first driving signal are respectively applied tothe first cells of the first layer, light incident on the first layer ismodulated into a first modulated light according to the first electricalsignals respectively applied to the first cells, and the first modulatedlight is output from the first layer; and controlling the second layerusing a second driving signal so that second electrical signalsgenerated based on the second driving signal are respectively applied tothe second cells of the second layer, the first modulated light receivedfrom the first layer is modulated into a second modulated lightaccording to the second electrical signals respectively applied to thesecond cells, and the second modulated light is output from the secondlayer, wherein a modulation resolution of the second modulated lightoutput from the second layer is greater than that of the first modulatedlight due to at least two second cells of the second layer that modulatelight modulated by one first cell of the first layer.
 2. The method ofclaim 1, wherein the first layer and the second layer are arranged sothat one second cell of the second layer modulates light modulated by atleast two first cells of the first layer.
 3. The method of claim 1,wherein at least one from among the first layer and the second layer isa reflective layer.
 4. The method of claim 1, wherein at least one fromamong the first layer and the second layer comprises at least one fromamong a liquid crystal on silicon (LCoS) and a deformable mirror (DM).5. The method of claim 1, wherein the first driving signal and thesecond driving signal are synchronized with each other so that a spaceresolution of the second modulated light output from the second layer isgreater than that of the first modulated light output from the firstlayer.
 6. The method of claim 1, wherein the first driving signal andthe second driving signal are synchronized with each other so that atime resolution of the second modulated light output from the secondlayer is greater than that of the first modulated light output from thefirst layer.
 7. The method of claim 1, wherein the first driving signaland the second driving signal are synchronized with each other in atemporally staggered manner.
 8. The method of claim 7, wherein a timedifference between a triggered time of the first driving signal and atriggered time of the second driving signal is shorter than at least onefrom among a period of the first driving signal and a period of thesecond driving signal.
 9. The method of claim 1, wherein a phase of thefirst driving signal is different from that of the second drivingsignal.
 10. The method of claim 9, wherein a phase difference betweenthe first driving signal and the second driving signal is shorter thanthe same period.
 11. The method of claim 1, wherein at least one fromamong the first cells and the second cells further modulate at least onefrom among a size and a phase of the light.
 12. The method of claim 1,wherein the first cells are arranged to be spatially shifted withrespect to the second cells, in a direction across a path of propagationof light.
 13. The method of claim 1, wherein the one first cell of thefirst layer overlaps the at least two second cells of the second layerwith respect to a path of propagation of light.
 14. An apparatuscontrolling a panel, comprising a first layer that includes first cellsdisposed adjacent to one another and a second layer that includes secondcells disposed adjacent to one another, the apparatus comprising: acontroller configured to: control the first layer using a first drivingsignal so that first electrical signals generated based on the firstdriving signal are respectively applied to the first cells of the firstlayer, light incident on the first layer is modulated into a firstmodulated light according to the first electrical signals respectivelyapplied to the first cells; and control the second layer using a seconddriving signal so that second electrical signals generated based on thesecond driving signal are respectively applied to the second cells ofthe second layer, the first modulated light received from the firstlayer is modulated into a second modulated light according to the secondelectrical signals respectively applied to the second cells, and thesecond modulated light is output from the second layer, wherein amodulation resolution of the second modulated light output from thesecond layer is greater than that of the first modulated light due to atleast two second cells of the second layer that modulate light modulatedby one first cell of the first layer.
 15. The apparatus of claim 14,wherein at least one from among the first layer and the second layer isa reflective layer.
 16. The apparatus of claim 14, wherein at least onefrom among the first layer and the second layer comprises at least onefrom among a liquid crystal on silicon (LCoS) and a deformable mirror(DM).
 17. The apparatus of claim 14, wherein the first driving signaland the second driving signal are synchronized with each other so that aspace resolution of the second modulated light output from the secondlayer is greater than that of the first modulated light output from thefirst layer.
 18. The apparatus of claim 14, wherein the first drivingsignal and the second driving signal are synchronized with each other sothat a time resolution of the second modulated light output from thesecond layer is greater than that of the first modulated light outputfrom the first layer.
 19. The apparatus of claim 14, wherein the firstdriving signal and the second driving signal are synchronized with eachother in a temporally staggered manner.
 20. The apparatus of claim 19,wherein a time difference between a triggered time of the first drivingsignal and a triggered time of the second driving signal is shorter thanat least one from among a period of the first driving signal and aperiod of the second driving signal.